Chromatography column structure



Oct. 26, 1965 H. A. GILL CHROMATOGRAPHY COLUMN STRUCTURE 4 Sheets-Sheet 1 Filed March 5, 1962 HTTOBNEX Oct. 26, 1965 H. A. GILL 3,213,596

CHROMATOGRAPHY COLUMN STRUCTURE Filed March 5, 1962 4 Sheets-Sheet 2 INVENTOR.

Oct. 26, 1965 H. A. GILL 3,213,596

CHROMATOGRAPHY COLUMN STRUCTURE Filed March 5, 1962 4 Sheets-Sheet 3 INVENTOR Harry 1? Gil Oct. 26, 1965 H. A. GILL 3,213,596

CHROMATOGRAPHY COLUMN STRUCTURE v Filed March 5, 1962 4 Sheets-Sheet 4 ZNVENTOR. 97719 H. GJZZ HTTOKNE'X BY W4.

United States Patent 3,213,596 CHROMATOGRAPHY COLUMN STRUCTURE Harry A. Gill, Ridgefield, Conn., assignor to The Perkin- Elmer Corporation, Norwalk, Conn, a corporation of New York Filed Mar. 5, 1962, Ser. No. 177,386 4 Claims. (Cl. 55-208) This invention relates to vapor phase chromatography and, more particularly, to a novel chromatographic column structure.

In chromatography, it is often desirable to program the temperature of the column throughout a range such that components having various boiling points will elute separately from the column. By proper programming, a large number of components may be detected and the usefulness of chromatography is thereby greatly extended. It is also desirable to be able to rapidly cool a column which has undergone such temperature programming. In this manner the column is more readily available for a subsequent analysis.

In prior art chromatography, temperature programming has been attempted by various methods. One such method is to place the column in a heated oven and rely on radiation and convection to provide the necessary heat. The primary ditficulty with this approach is that the thermal coupling between the heat source and the column is very loose. This makes accurate temperature control practically impossible.

Another approach which has been attempted is to wind the column in cylindrical form around a heated mandrel. This approach improves the coupling between the heat source and the column. However, as the column is heated it expands and thereby tends to move away from the mandrel. Thus, much of the improvement in heat coupling is lost and, furthermore, the thermal resistance becomes non-linear.

It is, therefore, the primary object of this invention to provide an improved temperature programmed chromatographic column.

Another object is to provide such a column having improved coupling between such column and the heat source.

Another object is to provide such a' column wherein expansion of the heated column does not destroy the improved coupling.

Another object is to provide such a column which may be rapidly cooled from its maximum temperature to a new starting temperature.

Other objects, features, and advantages will be apparent from the following description taken together with the figures of the attached drawings wherein:

FIG. 1 is a plan view, partially cut away, of an apparatus embodying this invention;

FIG. 2 is an elevational view of the apparatus of FIG.

FIG. 3 is a cross-sectional view of the column assembly taken along line 3-3 of FIG. 1;

FIG. 4 is a plan view, partially cut away, of the heater used with this invention;

FIG. 5 is a cross-section taken along line 5-5 of FIG. 4;

FIG. 6 is a plan view, partially cut away, of a typical column assembly for use with this invention;

FIG. 7 is a View taken along line 77 of FIG. 6;

FIG. 8 is an elevational view showing the mechanical construction of the heater mounting device of this invention; and

FIG. 9 is an overall schematic view of a chromatographic apparatus embodying this invention.

In accordance With this invention, a column is wound so as to lie in a single plane and to allow the two ends of the column to be exposed without crossovers. Such a planar wound column is then mounted in direct contact with a plate-like heater. The column and heater may be maintained in close thermal contact by means of a suitable clamping mechanism. In addition, passages for air or other cooling fluid may be provided along the surfaces of the heater-column combination and suitable means may be provided for passing cooling fluid therethrough.

The manner in which the column structure 11 of this invention is constructed will be best understood by reference to FIGS. 6 and 7. Two thin plates 10, 12 of a suitable heat conducting material such as aluminum are spot welded to opposite sides of a central core assembly made up of segments 14 and 16. The spacing provided between members 10 and 12 is such as to closely contact both sides of the chromatographic column 13 to be employed. Such a column may be either a Golay column or a packed column. The column is wound by passing approximately one-half the tube through the opening between spacers 14 and 16. The twoends of the column are then brought together and are spirally wound about the central core in the manner illustrated. It will be noted that the ends 18, 20 of the column may be brought out from the edge of the assembly without crossing over any previous turns. By this technique substantially the entire length of the column lies in a single plane and in excellent thermal contactwith the thin aluminum discs 10, 12. To complete the assembly, a circumferential spacer 22 is inserted around the edge of the assembly and theentire structure is suitably spot welded or riveted. The particular configuration of this type column will hereinafter be referred to as a double spiral.

The heater employed with this column is constructed as shown in FIG. 4. The heater 24 is a solid aluminum disc. The disc is cast to include a suitable electrical heating element 26 wound in double spiral form as was the column. In addition, a temperature sensing wire 28 is also cast into the assembly between the double spiral turns. Heating element 26 and temperature sensor 28 are insulated electrically from the aluminum disc. Suitable metallic positioning spacers 30 retain the elements in proper alignment during the casting process.

A cross-section of a completed heater assembly is shown in FIG. 3. It will be seen that a base plate 32 is provided with a number of ceramic insulators 34 which are mechanically fastened thereto by wires 35 through the insulators and inserted into holes in plate 32. The function of these spacers is to provide air cooling passages for channeling cool air from inlet air duct 36. The heating element 24 may be hinged as shown in FIG. 8 wherein hinge 38 is of the type that provides a degree of freedom in the vertical direction. Heater 24 may be pivoted downward to the position shown in FIG. 3, where it rests upon the ceramic spacers 34. The completed column assembly llis placed directly upon the surface of heater 24. A cover plate 40 is then positioned over the column. Cover plate 40 carries upon its surface a number of ceramic spacers 42 identical to spacers 34 which similarly form passages for cooling fluid across the surface of column assembly 11. The top and bottom of the complete assembly are covered with rigid heat insulation 44. A clamp mechanism including a U strap 46 and a thumb screw 48 holds the assembly together and provides adequate pressure on the heater-column assembly to insure good thermal contact.

It will be noted that this invention is not restricted to apparatus utilizing a single column. Two columns may advantageously be employed by positioning one above and one below heater 24.

Rapid cooling of the column of this invention is provided by cooling air duct 36 which receives air either from a blower 50 driven by a suitable motor 52 or from a compressed air supply 54. The housing for the heater- 3 column assembly may be of sheet metal provided with additional heat insulation 56 as required in addition to the rigid heat insulation 44.

FIG. 9 illustrates the manner in which the column 13 is connected into a chromatographic system. In this illustration 3. carrier gas supply conduit 58 provides carrier flow to a heated injector block 60. The carrier gas flows' through block 60, past assembly injection point 62 where it picks up the sample to be analyzed. Upon reaching a suitable stream splitter 64 a portion of the carrier-sample combination passes into conduit 66. The remainder is vented through waste line 68. The samplecarrier combination in line 66 passes into inlet 18 of column 13 where separation occurs. Upon leaving column 13 the various components are separately eluted through line 20 and eventually pass to a suitable mixing T 70. Mixing T 70 mixes the elutant with a fuel gas, such as hydrogen, supplied from line 72. The resulting mixture passes to a detector such as flame detector 74. The electrical signal from detector 74 is amplified by amplifier 76 and applied to a suitable recorder 78. Jumper 80, which is in the flow path between column 13 and mixing T 70, is provided in order that a second column may be easily inserted in series with column 13. This is accomplished by merely removing this jumper and connecting the second column inlet and outlet in its place. It will be understood that a detector of any suitable type may be used with this invention. The invention is not limited to use with a flame detector.

By means of this invention, extremely close coupling is provided between the heater and the column. The sensing wire 28 of the heater may be included in a bridge circuit for automatically programming the temperature of the assembly. In this way extremely accurate and linear temperature control is achieved. Furthermore, it

will be apparent that expansion of column 13 does not resultin any decrease in thermal coupling. All expansion of the column takes place in the plane in which it is positioned. The mechanical clamping between the heater and the column also insures against deterioration in thermal coupling. In addition, the provision of aircooling immediately adjacent the column and the heater provides unusually rapid return of the column to a temperature suitable for subsequent sample injection.

It will be apparent that many benefits and advantages accrue from this invention. It will be further apparent that this invention is capable of many variations and modifications without departing from the spirit thereof. It is, therefore, intended that this invention be limited only by the scope of the following claims.

I claim:

1. A chromatographic column assembly comprising:

a support member having a top surface;

a first plurality of spacers on the top surface of said support member defining a first group of air flow channels between said spacers;

a flat heater positioned on said first plurality of spacers;

a cover having a top and bottom side positioned parallel to and above said heater but spaced therefrom;

' a second plurality of spacers on the bottom side of said cover defining a second group of air flow channels between said second plurality of spacers;

and a chromatographic column sub-assembly including .a chromatographic column wound in a double spiral and having substantially its entire length in a common plane and a pair of heat conductive plates, one disposed on each side of said wound column and in direct physical contact with said column, said chromatographic column assembly positioned between said heater and said' second plurality of spacers and in direct physical contact with said heater and said second plurality of spacers.

2. A chromatographic column assembly comprising:

.a support member having a top surface;

a first plurality of spacers on the top surface of said support member defining a first group of air flow channels between said spacers;

a flat heater positioned on said first plurality of spacers;

a cover having a top and bottom side positioned parallel to and above said heater but spaced therefrom;

a second plurality of spacers on the bottom side of said cover defining a second group of air flow channels between said second plurality of spacers;

a chromatographic column sub-assembly including a chromatographic column wound in a double spiral and having substantially its entire length in a common plane and a pair of heat conductive plates, one disposed on each side of said wound column and in direct physical contact with said column, said chromatographic column assembly positioned between said heater and said second plurality of spacers and in direct physical contact with said heater and said second plurality of spacers;

and means for passing a cooling fluid through said first and second groups of air flow channels.

3. A chromatographic column assembly comprising:

a support member having a top surface and a bottom surface;

a first plurality of spacers on the top surface of said support member defining a first group of air flow channels between said spacers;

a flat heater positioned on said first plurality of spacers;

a cover having a top and bottom side positioned parallel to and above said heater but spaced therefrom;

a second plurality of spacers on the bottom side of said cover defining a second group of air flow channels between said second plurality of spacers;

a chromatographic column sub-assembly including a chromatographic column wound in a double spiral and having substantially its entire length in a common plane and a pair of heat conductive plates, one disposed on each side of said wound column and in direct physical contact with said column, said chromatographic column assembly positioned between said heater and said second plurality of spacers and in direct physical contact with said heater and said second plurality of spacers;

a first heat insulator positioned on the bottom surface of said support member;

and a second heat insulator positioned on the top side of said cover.

4. A chromatographic column assembly comprising:

a support member having a top surface and a bottom surface;

a first plurality of spacers on the top surface of said support member defining a first group of air flow channels between the spacers;

a flat heater positioned on said first plurality of spacers;

a cover having a top and bottom side positioned parallel to and above said heater but spaced therefrom;

a second plurality of spacers on the bottom side of said cover defining a second group of air flow channels between said second plurality of spacers;

a chromatographic column sub-assembly including a chromatographic column wound in a double spiral and having substantially its entire length in a common plane and a pair of heat conductive plates, one disposed on each side of said Wound column and in direct physical contact with said column, said chromatographic column assembly positioned between said heater and said second plurality of spacers and in direct physical contact with said heater and said second plurality of spacers;

means for passing a cooling fluid through said first and second group of air flow channels;

a first heat insulator positioned on the bottom surface of said support member;

5 a second heat insulator positioned on the top side of said cover; and a housing surrounding said chromatographic column assembly.

References Cited by the Examiner 5 UNITED STATES PATENTS 480,286 8/92 Serpollett 165-180 X 1,847,573 3/32 Rupp 165-180 X 2,169,852 8/39 Scott. 10 2,281,065 4/42 Lavigne 6217 X 2,300,634 11/42 Schoenfeld. 2,362,163 11/44 Shipman 261146 2,398,818 4/46 Turner 55--67 X 2,469,435 5/49 Hirsch 55-19 X 15 2,833,527 5/58 Kohl et a1. 261- -148 2,841,005 7/58 Coggeshall 55-197 X 2,868,011 1/59 Coggeshall 55-197 FOREIGN PATENTS Canada. Canada. Canada. France.

Great Britain.

OTHER REFERENCES Wisemann et 211.: German application 1,113,319, printed August 31, 1961, KL.421 4/16 (2 pp. dwg. 3 pp. spec.).

REUBEN FRIEDMAN, Primary Examiner. 

4. A CHROMATOGRAPHIC COLUMN ASSEMBLY COMPRISING: A SUPPORT MEMBER HAVING A TOP SURFACE AND A BOTTOM SURFACE; A FIRST PLURALITY OF SPACERS ON THE TOP SURFACE OF SAID SUPPORT MEMBER DEFINING A FIRST GROUP OF AIR FLOW CHANNELS BETWEEN THE SPACERS; A FLAT HEATER POSITIONED ON SAID FIRST PLURALITY OF SPACERS; A COVER HAVING A TOP AND BOTTOM SIDE POSITIONED PARALLEL TO AND ABOVE SAID HEATER BUT SPACED THEREFROM; A SECOND PLURALITY OF SPACERS ON THE BOTTOM SIDE OF SAID COVER DEFINING A SECOND GROUP OF AIR FLOW CHANNELS BETWEEN SAID SECOND PLURALITY OF SPACERS; A CHROMATOGRAPHIC COLUMN SUB-ASSEMBLY INCLUDING A CHROMATOGRAPHIC COLUMN WOUND IN A DOUBLE SPIRAL AND HAVING SUBSTANTIALLY ITS ENTIRE LENGTH IN A COMMON PLANE AND A PAIR OF HEAT CONDUCTIVE PLATES, ONE DISPOSED ON EACH SIDE OF SAID WOUND COLUMN AND IN DIRECT PHYSICAL CONTACT WITH SAID COLUMN, SAID CHROMATOGRAPHIC COLUMN ASSEMBLY POSITIONED BETWEEN SAID HEATER AND SAID SECOND PLURALITY OF SPACERS AND IN DIRECT PHYSICAL CONTACT WITH SAID HEATER AND SAID SECOND PLURALITY OF SPACERS; MEANS FOR PASSING A COOLING FLUID THROUGH SAID FIRST AND SECOND GROUPS OF AIR FLOW CHANNELS; A FIRST HEAT INSULATOR POSITIONED ON THE BOTTOM SURFACE OF SAID SUPPORT MEMBER; A SECOND HEAT INSULATOR POSITIONED ON THE TOP SIDE OF SAID COVER; AND A HOUSING SURROUNDING SAID CHROMATOGRAPHIC COLUMN ASSEMBLY. 